This proposal is for a new R21, Predicting genetic determinants of Zika virus emergence. This project aims to take a proactive approach to assessing how Zika may adapt to American vectors. Ultimately, this research will contribute to an expanding body of data and knowledge in the PI?s lab regarding the impact of specific, ecologically relevant vectors and hosts on arbovirus fitness determinants and population genetics. In particular, in this project we will determine how infection of Ae. aegypti, Ae. albopictus and Cx. quinquefasciatus influence ZIKV genetics. We will also assess the role of ambient temperature in shaping virus populations. Aim 1 focuses on characterizing vector competence of mosquito strains that originate from the Americas for the Asian lineage of ZIKV (i.e. the strain currently circulating in South America). We will then determine how the virus population changes as it passes through important tissue/compartments within each mosquito, including midguts, hemolymph, salivary glands and saliva. This aspect of the proposal is based on our ongoing work with West Nile virus and published literature on Chikungunya virus. The second aim is to assess how temperature influences virus mutational diversity during mosquito infection. This is a frequently asked, but never adequately answered question. Together, these aims will permit us to draw linkages across virus-vector systems and to provide predictions regarding likely adaptive mutations to the ZIKV genome that may permit more rapid spread in the Americas. The proposed research leverages extensive experience in virus-vector interactions, NGS and computational biology and a large amount of preliminary data on the WNV-Culex system.